This application is the national phase under 35 U.S.C. xc2xa7371 of PCT International Application No. PCT/JP98/01630 which has an International filing date of Apr. 9, 1998, which designated the United States of America.
The present invention relates to a front panel for a plasma display panel, which is attached to the front face of a plasma display panel and effectively shields electromagnetic waves generated by the plasma display panel.
Various computer displays used in office automation instruments and factory automation instruments, and displays of game machines and TVs radiate electromagnetic waves, and the influence of such electromagnetic waves on other equipment may cause problems.
Recently, plasma display panels (hereinafter referred to as xe2x80x9cPDPxe2x80x9d) attract attention as large-size display devices. However, electromagnetic waves generated by PDP often affect surroundings, for example, a FM broadcast picks up noise.
To shield such electromagnetic waves and avoid such an effect affection, various methods have been proposed, for example, a method wherein a filter for a display is utilized, which comprises a plastic substrate and a conductive film such as an indium oxide-tin oxide film formed on the surface of the substrate (JP-B-7-19551), a method wherein a display is covered with a fiber mesh made of polyester fiber metalized with nickel thereon, and a method wherein a filter is utilized, which comprises laminated glass plates and fine metal wires interposed between the plates, and the like.
However, a filter for a display having a conductive film such as an indium oxide-tin oxide film has a low performance of shielding electromagnetic waves and cannot effectively shield the electromagnetic waves. Thus, such a filter does not exhibit sufficient shielding properties against displays which generate intense electromagnetic waves such as PDP.
In the method wherein a display is covered with a mesh made of polyester fiber metalized with nickel thereon, dusts tend to be trapped with the mesh, and thus the screen of the display becomes indistinct for users.
When a filter comprising laminated glass plates and fine metal wires interposed between them is used, the visibility of a screen can be fairly improved, but it is very difficult to ground it, since the fine metal wires are interposed between the glass plates. Therefore, the electromagnetic wave-shielding properties cannot be maintained at a sufficient level for a long time.
In view of such circumstances, the present inventors made extensive research on front panels having electromagnetic wave-shielding properties, and have found that a front panel for a plasma display plate, which comprises a transparent resin plate and a conductive mesh placed thereon wherein a part of the conductive mesh is exposed in a sheet form on at least one side of the periphery of the front panel, can surely be grounded, stably exhibits high electromagnetic wave-shielding properties, and makes the screen of the display sufficiently visible. Thus, the present invention has been completed.
According to the first aspect, the present invention provides a front panel for a plasma display panel comprising at least one transparent resin plate and a conductive mesh placed on said transparent resin plate, in which a part of the conductive mesh is exposed on the plate in a sheet form on at least one side of the marginal surface of the front panel.
According to the second aspect, the present invention provides a front panel for a plasma display panel according to the first aspect, in which uneven patterns (asperity) are formed on at least one side of surfaces of the front panel.
According to the third aspect, the present invention provides a front panel for a plasma display panel according to the first aspect, which further comprises an intermediate synthetic resin plate placed between the transparent resin plate and the conductive mesh, and a decorative portion provided between the intermediate synthetic resin plate and the transparent resin plate.
According to the fourth aspect, the present invention provides a front panel for a plasma display panel according to the first aspect, which further comprises a conductive film, a part of which is in contact with the conductive mesh in a sheet form on at least one side of the marginal surface of the front panel.
According to the fifth aspect, the present invention provides a front panel for a plasma display panel according to the first aspect, in which the transparent resin plate has properties of shielding near-infrared rays.